Aluminum bronze alloy containing vanadium and having improved wear resistance



States 3,062,642 ALUMINUM BRONZE ALLOY CONTAINING VANADIUM AND HAVING IMPROVED WEAR RESISTANCE John F. Klement, Milwaukee, Wis., assignor to Arnpco Metal, Inc., Milwaukee, Wis., a corporation of Wiscousin No Drawing. Filed Feb. 23, 1961, Ser. No. 90,939 6 Claims. (Cl. 75162) This invention relates to an aluminum bronze alloy and more particularly to an aluminum bronze alloy containing a small addition of vanadium and having improved wear resistance.

In drawing operations for sheet and plate alloys such as stainless steel, aluminum, nickel, titanium, mild steel and some copper base alloys, the dies are often fabricated from aluminum-bronze alloys. The aluminum bronze alloys used in die applications have good corrosion resistance, wear resistance and are non-galling against many wrought materials.

The aluminum bronze alloys which in the past have shown the optimum properties for deep drawing dies are those which contain approximately 14% aluminum, a small amount of iron and the balance copper. Alloys of this type have good corrosion resistance and non-galling properties. However, under heavy use in die applications, an alloy of this type wears undesirably fast so that close dimensional tolerances cannot be maintained because of the wear that occurs in the die surface.

The present invention is directed to an aluminum bronze alloy which has the corrosion resistance and the non-galling properties characteristic of aluminum bronze alloys, but has improved wear resistance, toughness and hardness. These increased physical properties are brought about by the addition of a small amount of vanadium. The vanadium tends to make the alloy more homogeneous in the distribution of the metallurgical phases and compounds during solidification and heat treatment and also promotes uniform, controlled grain size.

The alloy of the invention has the following general composition by weight:

Percent Aluminum 13.0-18.0 Iron 2.0-6.0 Vanadium 0.5 2.5

Copper Balance The alloy falling within the above range of composition has a tensile strength in the range of 70,000 to 100,000 p.s.i., a yield strength of 50,000 to 80,000 psi, an elongation in two inches up to 3% and a Rockwell C hardness in the range of 25 to 50.

A specific illustration of the composition of the alloy falling within the above range is as follows in weight percent:

Percent Aluminum 14.50

Iron 4.25 Vanadium 1.00 Copper 80.25

resistance over the conventional aluminum-iron-copper alloy due to the addition of vanadium. The wear resistance of the alloy is determined on a rolling-slip friction device such as an Amsler wear test machine. In the test procedure, a cylindrical aluminum bronze alloy test specimen is subjected to rolling and sliding motions against an 18-8 stainless steel cylinder of identical dimensions with a 25 kilogram load applied on the specimens. The wear rate is determined by the weight loss of the test specimen in 1000 revolutions in the testing procedure.

With a wear test procedure such as this, a standard aluminum bronze die alloy containing 14.5% aluminum, 4.5% iron and 81.0% copper had a wear rate or weight loss of 0.00410 gram per 1000 revolutions and a Rockwell C hardness of 39. In comparison with this, the alloy of the invention, containing 14.26% aluminum, 4.39% iron, 1.02% vanadium and 80.33% copper, had a wear rate of 0.00360 gram per 1000 revolutions and a Rockwell C hardness of 39. From these test results it can be seen that the wear resistance of the alloy was substantially increased by the addition of vanadium, while the hard ness of the alloy was not increased to any great extent.

Generally, the wear rate of the alloy of the invention containing the vanadium addition is in the range of 0.0020 to 0.0040 gram per 1000 revolutions per 25 kilogram load, as measured by an Amsler wear testing machine against 18-8 stainless steel. In addition, the alloy has a hardness in the range of 25 Rockwell C to 55 Rockwell C, depending on the specific aluminum, iron and vanadium contents in the alloy.

The alloy of the invention has greatly improved wear resistance over that of an ordinary aluminum bronze alloy and this increase in wear resistance is most significant since the hardness of the alloy is not appreciably changed over the aluminum bronze alloy having similar proportions of aluminum and iron, but not containing the vanadium. This unexpected increase in wear resistance without an increase in hardness is believed to be due to the formation of an intermetallic compound formed predominantly of iron and vanadium and containing aluminum and copper. This intermetallic compound in the form of small particles is extremely hard and resistant to wear.

The metallographic structure of the alloy consists essentially of a gamma two phase which is uniformly distributed in a matrix of beta. The intermetallic compound composed if iron, vanadium, aluminum and copper exists in small particles of uniform size and shape which are distributed throughout the phases.

If the vanadium content of the alloy is increased over 2.5%, additional quantities of vanadium will come out of solution as intermetallic particles, which will make the particles extremely rich in vanadium and cause pickup or galling of the workpiece. If the vanadium content is reduced below the lower limit of the aforementioned range, there is no appreciable effect shown in the increase 111 wear resistance.

In order to obtain optimum properties, the metal used for the alloy should be of high quality. Electrolytic or wrought fire-refined copper, high purity aluminum, low carbon iron, and high purity vanadium are preferred to be used. It has been found that the best method of obtaining the desired uniformity in the alloy is by using a double melting procedure whereby a pre-alloy is made. The pre-alloy is one that has approximately 60% aluminum, 20% iron and 20% copper. In the melting procedure, this pre-alloy is melted in the crucible with an additional quantity of copper and after melting, a vanadium-aluminum alloy is added to the melt. Alternately, the vanadium can be employed in the pre-alloy which, if containing vanadium, will generally consist of 60% aluminum, 15% iron, 15% copper and 10% vanadium.

To establish complete uniformity of the microstructure and hardness, the alloy can be heat treated at an elevated temperature in the range of 1000 F. to 1200 F. with a temperature of about 1150 F. being preferred. The alloy is held at the temperature in this range for a period sufiicient to obtain a uniform distribution of temperature and generally for a period of about 1 hour plus /2 hour per inch of section thickness greater than one inch, up to a maximum of 2 /2 hours at that temperature. After the required soaking time at the elevated temperature, the alloy is air-cooled at a rate faster than about 20 F. per hour per one inch of section thickness.

The alloy of the invention can be used to produce articles for wear resistant application in drawing and forming operations. The articles may take the form of deep drawing dies, hold down dies, wear guides, forming rolls, skids, slides and the like.

The alloy can also be extruded into weld rods and weld wire. The alloy in the form of coated or uncoated weld rod can be overlaid on a metal base by metal spraying or other welding methods such as heliarc, carbonarc, metalarc and the like, to obtain a corrosion-resistant wear surface.

Various modes of carrying out the invention are contemplated as being within the scope of the following claims particularly pointing out and distinctly claiming the subject matter which is regarded as the invention.

I claim:

1. An aluminum bronze alloy, consisting essentially by weight of 13.0 to 18.0% aluminum, 2.0 to 6.0% iron, 0.50 to 2.5% vanadium and the balance being copper, said alloy being characterized by having excellent corrosion resistance and improved toughness and wear resistance.

2. An aluminum bronze alloy, consisting essentially by weight of 13.0 to 18.0% aluminum, 2.0 to 6.0% iron, 0.50 to 2.5% vanadium and the balance being copper, said alloy being characterized by a tensile strength in the 4 range of 70,000 to 100,000 p.s.i., a yield strength in the range of 50,000 to 80,000 p.s.i., an elongation in two inches of up to 3%, and hardness in the range of 25 to Rockwell C.

3. An aluminum bronze alloy, consisting essentially by weight of 13.0 to 18.0% aluminum, 2.0 to 6.0% iron, 0.50 to 2.5% vanadium and the balance being copper, said alloy having a wear rate in the range of 0.0020 to 0.0040 gram per 1000 revolutions per 25 kilogram load of frictional work as measured on a rolling-slip wear testing machine against 18-8 strainless steel.

4. A deep drawing die characterized by having excellent corrosion resistance, a hardness in the range of 25 to 50 Rockwell C and improved wear resistance, said dies being fabricated from an aluminum bronze alloy consisting essentially by weight of 13.0 to 18.0% aluminum, 2.0 to 6.0% iron, 0.50 to 2.5 vanadium and the balance being copper.

5. An aluminum bronze alloy, consisting essentially of 14.5% aluminum, 4.25% iron, 1.0% vanadium and 80.25% copper, said alloy being characterized by having excellent corrosion resistance and improved toughness and wear resistance.

6. An aluminum bronze welding electrode, consisting essentially by weight of 13.0 to 18.0% aluminum, 2.0 to 6.0% iron, 0.50 to 2.5 vanadium and the balance being copper.

References Cited in the file of this patent UNITED STATES PATENTS 2,874,042 Klement Feb. 17, 1959 2,937,941 Klement May 24, 1960 2,944,889 Klement July 12, 1960 2,944,890 Klement July 12, 1960 FOREIGN PATENTS 333,442 Great Britain Aug. 14, 1930 

1. AN ALUMINUM BRONZE ALLOY CONSISTING ESSENTIALLY BY WEIGHT OF 13.0 TO 18.0% ALUMINUM, 2.0 TO 6.0% IRON, 0.50 TO 2.5% VANADIUM AND THE BALANCE BEING COPPER, SAID ALLOY BEING CHARACTERIZED BY HAVING EXCELLENT CORROSION RESISTANCE AND IMPROVED TOUGHNESS AND WEAR RESIST-ANCE. 